How can I remove last filter from an appender in runtime? I can clear the filters, I can add a filter, but both methods alter private property m_tailFilter so when I set the Next property to null for the one before last filter, adding new filters afterwards does not work.
appender.AddFilter(filter); // works fine
appender.ClearFilters(); // works fine and adding filter again also works
var lastFilter = appender.FilterHead; // save previously last filter
appender.AddFilter(filter); // works fine
filter.Next = null; // works fine, i.e. removes the last filter
appender.AddFilter(filter); // doesn't work, i.e. this filter is ignored
I will post here what I came with. I don't like it, it feels hacky and I think that there should be a better approach, but it seems to work for my scenario.
filter.Next = null;
var f = appender.FilterHead;
appender.ClearFilters();
appender.AddFilter(f);
So after removing the last filter from the chain, clear all filters and add the head again, this sets the tail correctly.
Related
Take a windowed virtual list with the capability of loading an arbitrary range of rows at any point in the list, such as in this following example.
The virtual list provides a callback that is called anytime the user scrolls to some rows that have not been fetched from the backend yet, and provides the start and stop indexes, so that, in an offset based pagination endpoint, I can fetch the required items without fetching any unnecessary data.
const loadMoreItems = (startIndex, stopIndex) => {
fetch(`/items?offset=${startIndex}&limit=${stopIndex - startIndex}`);
}
I'd like to replace my offset based pagination with a cursor based one, but I can't figure out how to reproduce the above logic with it.
The main issue is that I feel like I will need to download all the items before startIndex in order to receive the cursor needed to fetch the items between startIndex and stopIndex.
What's the correct way to approach this?
After some investigation I found what seems to be the way MongoDB approaches the problem:
https://docs.mongodb.com/manual/reference/method/cursor.skip/#mongodb-method-cursor.skip
Obviously he same approach can be adopted by any other backend implementation.
They provide a skip method that allows to skip an arbitrary amount of items after the provided cursor.
This means my sample endpoint would look like the following:
/items?cursor=${cursor}&skip=${skip}&limit=${stopIndex - startIndex}
I then need to figure out the cursor and the skip values.
The following code could work to find the closest available cursor, given I store them together with the items:
// Limit our search only to items before startIndex
const fragment = items.slice(0, startIndex);
// Find the closest cursor index
const cursorIndex = fragment.length - 1 - fragment.reverse().findIndex(item => item.cursor != null);
// Get the cursor
const cursor = items[cursorIndex];
And of course, I also have a way to know the skip value:
const skip = items.length - 1 - cursorIndex;
I created an ActivityNode (an Entry) and I can add custom fields with the
setFields(List<Field> newListField)
fonction.
BUT
I am unable to modify these fields. (In this case I try to modify the value of the field named LIBENTITE)
FieldList list = myEntry.getTextFields();
List<Field> updatedList = new ArrayList<Field>();
//I add each old field in the new list, but I modify the field LIBENTITE
for(Field myField : list){
if(myField.getName().equals("LIBENTITE")){
((TextField)myField).setTextSummary("New value");
}
updatedList.add(myField);
}
myEntry.setFields(updatedList);
activityService.updateActivityNode(myEntry);
This code should replace the old list of fields with the new one, but I can't see any change in the custom field LIBENTITE of myEntry in IBM connections.
So I tried to create a new list of fields, not modifying my field but adding a new one :
for(Field myField:list){
if(!myField.getName().equals("LIBENTITE")){
updatedList.add(myField);
}
}
Field newTextField = new TextField("New Value");
newTextField .setFieldName("LIBENTITE");
updatedList.add(newTextField );
And this code is just adding the new field in myEntry. What I see is that the other custom fields did not change and I have now two custom fields named LIBENTITE, one with the old value and the second with the new value, in myEntry.
So I though that maybe if I clear the old list of Fields, and then I add the new one, it would work.
I tried the two fonctions
myEntry.clearFieldsMap();
and
myEntry.remove("LIBENTITE");
but none of them seems to work, I still can't remove a custom field from myEntry using SBT.
Any suggestions ?
I have two suggestions, as I had (or have) similar problems:
If you want to update an existing text field in an activity node, you have to call node.setField(fld) to update the field in the node object.
Code snippet from my working application, where I'm updating a text field containing a (computed) start time:
ActivityNode node = activityService.getActivityNode(id);
node.setTitle(formatTitle()); // add/update start and end time in title
boolean startFound = false;
// ...
FieldList textfields =node.getTextFields();
Iterator<Field> iterFields = textfields.iterator();
while (iterFields.hasNext()) {
TextField fld = (TextField) iterFields.next();
if (fld.getName().equals(Constants.FIELDNAME_STARTTIME)) {
fld.setTextSummary(this.getStartTimeString()); // NOTE: .setFieldValue does *not* work
node.setField(fld); // write updated field back. This seems to be the only way updating fields works
startFound=true;
}
}
If there is no field with that name, I create a new one (that's the reason I'm using the startFound boolean variable).
I think that the node.setField(fld) should do the trick. If not, there might be a way to sidestep the problem:
You have access to the underlying DOM object which was parsed in. You can use this to tweak the DOM object, which finally will be written back to Connections.
I had to use this as there seems to be another nasty bug in the SBT SDK: If you read in a text field which has no value, and write it back, an error will be thrown. Looks like the DOM object misses some required nodes, so you have to create them yourself to avoid the error.
Some code to demonstrate this:
// ....
} else if (null == fld.getTextSummary()) { // a text field without any contents. Which is BAD!
// there is a bug in the SBT API: if we read a field which has no value
// and try to write the node back (even without touching the field) a NullPointerException
// will be thrown. It seems that there is no value node set for the field. We
// can't set a value with fld.setTextSummary(), the error will still be thrown.
// therefore we have to remove the field, and - optionally - we set a defined "empty" value
// to avoid the problem.
// node.remove(fld.getName()); // remove the field -- this does *not* work! At least not for empty fields
// so we have to do it the hard way: we delete the node of the field in the cached dom structure
String fieldName = fld.getName();
DeferredElementNSImpl fldData = (DeferredElementNSImpl) fld.getDataHandler().getData();
fldData.getParentNode().removeChild(fldData); // remove the field from the cached dom structure, therefore delete it
// and create it again, but with a substitute value
Field newEmptyField = new TextField (Constants.FIELD_TEXTFIELD_EMPTY_VALUE); // create a field with a placeholder value
newEmptyField.setFieldName(fieldName);
node.setField(newEmptyField);
}
Hope that helps.
Just so that post does not stay unanswered I write the answer that was in a comment of the initial question :
"currently, there is no solution to this issue, the TextFields are read-only map. we have the issue recorded on github.com/OpenNTF/SocialSDK/issues/1657"
I have a 2 column sorted view and try to get a document the following code:
var searchArr = new java.util.Vector();
searchArr.addElement(10000310);
searchArr.addElement(45);
var customerdoc:NotesDocument = viw.getDocumentByKey(searchArr,true);
but the result is null.
If I use only the first element for the key (10000310), then I get (the first) doc with that key. But with the 2-element-vector the lookup returns null.
the same in LotusScript works fine:
Dim searchkey(1) As Double
searchkey(0) = 10000307
searchkey(1) = 45
Set doc = luview.Getdocumentbykey(searchkey, true)
gives me the document I need.
Confusing, for me ....
Uwe
This is a known bug, hopefully to be fixed in 9.0.2. See this question getDocumentByKey with view category separated by "\\" in XPages
Your LS example uses an array, not a Vector. I am not even sure if it is intended to work with a Vector - never did that. So just use an array here, too, as the key.
I seem to be having a problem with assigning values to fields of a content item with a custom content part and the values not persisting.
I have to create the content item (OrchardServices.ContentManager.Create) first before calling the following code which modifies a field value:
var fields = contentItem.As<MyPart>().Fields;
var imageField = fields.FirstOrDefault(o => o.Name.Equals("Image"));
if (imageField != null)
{
((MediaLibraryPickerField)imageField).Ids = new int[] { imageId };
}
The above code works perfectly when against an item that already exists, but the imageId value is lost if this is done before creating it.
Please note, this is not exclusive to MediaLibraryPickerFields.
I noticed that other people have reported this aswell:
https://orchard.codeplex.com/workitem/18412
Is it simply the case that an item must be created prior to amending it's value field?
This would be a shame, as I'm assigning this fields as part of a large import process and would inhibit performance to create it and then modify the item only to update it again.
As the comments on this issue explain, you do need to call Create. I'm not sure I understand why you think that is an issue however.
I have a custom entity named eld_timereg. This entity has an attribute named eld_name (which is the primary field). Records are created in a generic handler (after pushing a button in the ribbon). I'm using late binding.
var myService = ...;
var t = new Entity( "eld_timereg" );
t["field1"] = "abc";
.
.
.
t["eld_name"] = GenerateAnUniqueStringCode("ZXC");
// returns something like ZXC-16398-T1VC
return myService.Create(t);
The record is created without any error. Checking the entity in SSMS, the value is blank although it is a required field.
What is happening here?
Found the problem. You put me on the right track James. Thank you for that. The eld_name attribute was overwritten in the plug-in (I forgot). Here it should be filled with some information. This was going wrong and always returned a null.